1. Field of the Invention
The present invention relates to a rehabilitating pipe segment adapted for use to rehabilitate existing pipes by linking a plurality of segments in the circumferential direction and pipe length direction, and to a rehabilitation method using this segment to rehabilitate existing pipes.
2. Description of the Related Art
There are pipe rehabilitation methods known in the art for linking a plurality of segments in the circumferential direction and pipe length direction to assemble a rehabilitating pipe when sewerage pipes, waterworks pipes, agricultural water pipes, and other existing pipes have aged. A filler is used to fill the space between the rehabilitating pipe and existing pipe so as to integrate both the pipes together and construct a composite pipe (JP-A-2003-286742 and JP-A-2005-299711).
The rehabilitating pipe segment is an assembly unit for a rehabilitating pipe and comprises an internal surface plate, side plates, and end plates, these plates being integrally molded from a transparent or nontransparent plastic material in the form of a block. Reinforcing plates and ribs are preferably provided to increase the strength of the segment.
The existing pipe described above is formed by connecting a plurality of pipes of a specified length, and the seams in the existing pipe therefore occasionally separate when an earthquake or some other great force acts on the exterior. In cases in which the existing pipe has been rehabilitated using the segments described above, the seam portions or portions in the vicinities of the seams will rupture under the tension in the rehabilitating pipe integrated with the existing pipe. This is because the width dimension of the segment constituting the rehabilitating pipe is fixed and cannot be expanded or contracted by tension. In the case that the existing pipe is a sewerage pipe, external liquefied sediment flows in through ruptured portions of the sewerage pipe between separated seams of the sewerage pipe, compromising the function of the sewerage pipe.
When a curved existing pipe is being rehabilitated, the segment requires special machining as well, such as cutting the segment at a slant in relation to the curve, and there have been problems in that the curved rehabilitating pipe cannot be assembled in a simple manner.